1. Field of the Invention
The invention relates to an instrument for emergency treatment of i.a. respiratory obstruction in humans, of the kind indicated in the preamble of the enclosed claim 1, and also relates to an appropriate use for the instrument.
2. Description of the Prior Art
Epiglottitis and other acute so called upper respiratory obstructions, which may e.g. be caused by a foreign object, allergic reactions, insect-bites in or injury to mouth and throat etc., are especially with children, but also with adults, dramatic problems. All health care facilities giving emergency care must have full capacity for correct and adequate treatment of such medical problems. Readiness must also be at hand within ambulance medical service, surgical medical service and military medical service. With the exception of specialist medical service the active readiness is, however, at present not satisfactory in practice since there is no simple, safe and appropriate instrument available for relieving the above mentioned conditions. Instruments have been developed such as the expensive and by many physicians dreaded cricothyroid membrane cutting device or coniotome (see e.g. Swedish patent application No. 7316352-9) which moreover is not recommended for use on small children under 5-6 years of age. Any other quite adequate instrument is neither available in practice nor discussed in the literature, which means that in an acute situation a great majority of physicians, not to mention other trained medical personnel, are left without any actual professional means of action and are rather thrown upon mere chance or their own more or less successful initiative. In the above discussed situations involving upper respiratory obstruction where the acute condition calls for an unobstructed airway and adequate respiratory assistance (in many cases the patient suffers from marked hypercapnia with weak or arrested spontaneous respiration) there is only one method available, namely tracheotomy, which is a potentially dangerous measure which almost without exception is performed in the operating rooms of hospitals. As a rule there is not enough time to perform a tracheotomy in cases of acute, high-grade upper respiratory obstruction, and this is generally true even if the patient already has arrived in an acute hospital offering emergency-surgery. Instead one of the five methods indicated below is used and these, at best, only provide for an adequate unobstructed airway but seldom or never provide for adequate respiratory assistance. Said five methods are:
1. Bag ventilation through mask, which is mostly impossible to perform in cases of acute epiglottitis or other forms of high-grade upper respiratory obstruction.
2. Tracheal intubation which even for the trained anesthesiologist often involves great difficulties or is regarded as impossible.
3. Cricothyroidotomy by means of a scalpel which is a surgical operation that in practice is used only as a last resort by specialists or physicians without any other alternative means of action. This method involves considerable danger and does not provide any immediate possibility for giving respiratory assistance, including oxygen supply.
4. Cricothyroidotomy by means of the above mentioned coniotome which, in principle, is the same course of action as under item 3. Here an instrument is used which makes the operation "semi-automatical" and which facilitates the introduction of a fine tube or the like. As mentioned above this emergency treatment is, however, medically unattractive to most physicians and in practice it is never used in spite of the fact that most medical students in Scandinavia receive instruction about use of the so called coniotome which is available as standard equipment in most health-care facilities offering acute care. A coniotome is only used as a last resort in an extreme emergency and moreover this method is not appropriate for use on children up to 5-6 years of age.
5. Percutaneous puncture of the cricothyroid membrane by means of a thick cannula, e.g. a larger type of cannula used for filling syringes or a large bore cannula for punction of the knee joint cavity. At present this is the most available method for children and of the invasive methods it is regarded to be the least dangerous one. Furthermore the expert opinion is that this method may give the patient a satisfactory possibility for respiration. The basis for this is that most upper respiratory obstructions form a one way valve above, at or just below the level of the vocal cords. Respiratory gas at positive pressure may be introduced through a relatively thin cannula and expiration is often possible past the respiratory obstruction, if necessary, by means of supportive compression of the thorax. Occasionally it is recommended to insert two needles in order to increase the cross-section area for inspiration. This method is however, associated with risks, e.g. injuries to the posterial wall of the trachea or to the oesophagus, mucous membrane mediastinal and subcutaneous emphysema among others. Worse is, however, the fact that the respiratory assistance which is often vital, cannot be given in a satisfactory manner. The physician is reduced to using mouth-to-cannula ventilation which is both impractical, difficult and ineffective. Oxygen may generally only be supplied if the patient is breathing spontaneously, and even then with an imminent danger of extinguishing the breathing reflexes of a patient in sleep, induced by marked hypercapnia, and the physician is once more reduced to using the above mentioned mouth-to-cannula ventilation in order to assist breathing. The position of the cannula may easily be inadvertently displaced and this may cause substantial injuries with bleeding down into the airways, since the cannula is nonresilient and its point sharp and non-flexible. It may also easily happen that the cannula is displaced from its proper position, which means that any respiratory assistance must be immediately stopped and the puncture repeated.
The patient, if not unconscious, must lie absolutely still if trauma from the hard and sharp needle is to be avoided. Thus it is evident that there is presently no safe, easy and efficient method available for providing free airway and for giving active respiratory assistance in the above mentioned acute situations.
Another example of a situation where it is presently not possible to give respiratory assistance without extremely serious consequences is in traffic accidents where a person suffering from a fractured cervical spine unconsciousness and/or difficulty in breathing, may remain sitting in the vehicle seat with the safety belt fastened and with his chin flexed down towards the chest. The only possibility for the ambulance personnel to give respiratory assistance is to flex the injured persons head backwards and to ventilate e.g. through a mask. If the cervical spine is fractured such a backward flexion of the head involves a very great danger of injuring the spinal cord which can cause the immediate death of the patient or leave a permanent neurological disability (e.g. tetraplegia).
In other situations involving respiratory arrest (e.g. Myocardial infarction with cardiac and respiratory arrest) great difficulties may often be encountered when conventional equipment is used for artificially ventilating the patient or giving him vital pharmaceuticals.
The objective of the invention is to provide an instrument of the kind mentioned in the introduction, eliminating the shortcomings of the above discussed prior methods and at the same time being relatively uncomplicated and thus simple and inexpensive to manufacture.